Emulators allow you to play practically any game one your computer. from the classic NES and even virtuaboy to newer consoles like the 360. Here is how to get one.
Step 1. Go to http://www.emulator-zone.com/doc.php/nes/
step 2. Look on the left hand side of the screen and choose what emulator you want, you will be directed to a new page.
Step 3. Scroll down until you see "Emulators"
Step 4. Click one of the links, I am going to use NES so i click the Jnes.
Step 5. Download the file and save.
Step 6. When i opened Jnes i was prompt to extract to specified folder, DO NOT just hit continue because you will have to know where to find it.
Step 7. When you have completed the above steps you will need games.
Step 8. Go to http://www.coolrom.com/
Step 9. On the top bar it will say "Rom Files" click there
Step 10. Choose your system. I chose nintendo.
Step 11. Browse the games until you find one you want.
Step 12. Click the game and scroll down.
Step 13. Wait 12 seconds until it says "Download your file" and click it
Step 14. Open it using WinRaR
Step 15. Click the game file and hit "Extract To"
Step 16. Extract it to the folder with the emulator
Step 17. Run the emulator and the game should be there, if not hit file>Open and then find your ROM
Winrar download:
http://www.rarlab.com/